Recently, thinning and miniaturization of a semiconductor device and its package have been increasingly demanded. Therefore, as the semiconductor device and its package, flip chip type semiconductor devices in which a semiconductor element such as a semiconductor chip is mounted (flip chip-connected) on a substrate by means of flip chip bonding have been widely utilized. In such flip chip connection, a semiconductor chip is fixed to a substrate in a form where a circuit face of the semiconductor chip is opposed to an electrode-formed face of the substrate. In such a semiconductor device or the like, there may be a case where the back surface of the semiconductor chip is protected with a protective film to prevent the semiconductor chip from damaging or the like (see, Patent Document 1 to 10).    Patent Document 1: JP-A-2008-166451    Patent Document 2: JP-A-2008-006386    Patent Document 3: JP-A-2007-261035    Patent Document 4: JP-A-2007-250970    Patent Document 5: JP-A-2007-158026    Patent Document 6: JP-A-2004-221169    Patent Document 7: JP-A-2004-214288    Patent Document 8: JP-A-2004-142430    Patent Document 9: JP-A-2004-072108    Patent Document 10: JP-A-2004-063551
However, in order to protect a back surface of a semiconductor chip by the protective film, it is necessary to add a new step for attaching the protective film to the back surface of the semiconductor chip obtained in a dicing step. As a result, the number of steps increases and production cost and the like increase. Accordingly, for the purpose of reducing the production cost, the present inventors have developed a dicing tape-integrated film for semiconductor back surface. The dicing tape-integrated film for semiconductor back surface has a structure including a dicing tape having a base material and a pressure-sensitive adhesive layer on the base material, and a film for flip chip type semiconductor back surface formed on the pressure-sensitive adhesive layer of the dicing tape. At the production of the semiconductor device, the dicing tape-integrated film for semiconductor back surface is used as follows. First, a semiconductor wafer is attached onto the film for flip chip type semiconductor back surface in the dicing tape-integrated film for semiconductor back surface. Next, the semiconductor wafer is diced to form a semiconductor element. Subsequently, the semiconductor element is peeled from the pressure-sensitive adhesive layer of the dicing tape and picked up together with the film for flip chip type semiconductor back surface and then the semiconductor element is flip chip-connected onto an adherend such as a substrate. Consequently, a flip chip type semiconductor device is obtained. However, in the dicing tape-integrated film for semiconductor back surface described in the above, in the case where close adhesiveness of the pressure-sensitive adhesive layer with the film for flip chip type semiconductor back surface is high, picking-up of the semiconductor element becomes difficult in some cases.
With regard to the picking-up property of the semiconductor element, the present inventors have further developed a dicing tape-integrated film for semiconductor back surface including a pressure-sensitive adhesive layer cured beforehand by irradiation with a radiation ray. Since this dicing tape-integrated film for semiconductor back surface exhibits a good peeling property between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface at the picking-up of the semiconductor element without irradiation with a radiation ray, the picking-up property is improved. Furthermore, since a step of irradiation with a radiation ray is unnecessary, the number of production steps for producing a semiconductor device can be decreased and also the production cost can be reduced.
However, in such a dicing tape-integrated film for semiconductor back surface described in the above, since the pressure-sensitive adhesive layer has been radiation-cured beforehand, the close adhesiveness between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface is low. Therefore, for example, there is a problem that chip fly and chipping of the semiconductor element occur at dicing of the semiconductor wafer. In addition, there is also a problem that cutting water used at dicing penetrates between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface.
The present invention has been made in consideration of the foregoing problem and an object thereof is to provide a dicing tape-integrated film for semiconductor back surface capable of preventing the occurrence of chip fly and chipping of the semiconductor element at the dicing of the semiconductor wafer and the penetration of cutting water used in the dicing between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface while maintaining a good peeling property at the picking-up of the semiconductor element, and a process for producing a semiconductor device.
In order to solve the foregoing problems, the present inventors made extensive and intensive investigations. As a result, it has been found that the foregoing problems can be solved by adopting the following configuration, thereby leading to accomplishment of the invention.
Namely, the present invention provides a dicing tape-integrated film for semiconductor back surface, comprising a film for flip chip type semiconductor back surface for protecting a back surface of a semiconductor element flip chip-connected onto an adherend, and a dicing tape,
the dicing tape comprising a base material and a pressure-sensitive adhesive layer provided on the base material,
the film for flip chip type semiconductor back surface being formed on the pressure-sensitive adhesive layer,
wherein the pressure-sensitive adhesive layer is a radiation-curable pressure-sensitive adhesive layer whose pressure-sensitive adhesive force toward the film for flip chip type semiconductor back surface is decreased by irradiation with a radiation ray.
According to the foregoing configuration, since the close adhesiveness between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface is good, for example, the occurrence of chip fly and chipping of the semiconductor element at the dicing of the semiconductor wafer can be prevented. Here, at the dicing, for example, the semiconductor wafer is cut by rotating a dicing blade or the like at high speed, and the cutting is generally performed with spraying cutting water on the cutting part for cooling and preventing flying of cut swarf. According to the invention, since the close adhesiveness between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface is good, it is possible to prevent the cutting water from penetrating between the both. Furthermore, in the foregoing configuration, since a radiation-curable type pressure-sensitive adhesive layer is used as the pressure-sensitive adhesive layer, decrease in the pressure-sensitive adhesive force toward the film for flip chip type semiconductor back surface can be achieved by irradiating the pressure-sensitive adhesive layer with a radiation ray immediately before picking-up of the semiconductor element, for example. Consequently, at the picking-up of the semiconductor element together with the film for flip chip type semiconductor back surface, the picking-up can be well performed without generating adhesive residue. Incidentally, the back surface of the semiconductor element means a face (non-circuit face) opposite to the circuit-formed face (circuit face).
The film for flip chip type semiconductor back surface preferably contains a colorant. Owing to this constitution, the film for flip chip type semiconductor back surface can have a function of exhibiting an excellent laser marking property and an excellent appearance property. As a result, for example, marking can be performed to impart various kinds of information such as literal information and graphical information to the face on the non-circuit side of the semiconductor element or a semiconductor device using the semiconductor element by utilizing any of various marking methods such as a printing method and a laser marking method through the film for flip chip type semiconductor back surface. Moreover, the film for flip chip type semiconductor back surface and the dicing tape can be easily distinguished from each other and hence workability and the like can be enhanced.
Furthermore, the present invention also provides a process for producing a semiconductor device using the above-mentioned dicing tape-integrated film for semiconductor back surface, the process comprising:
attaching a semiconductor wafer onto the film for flip chip type semiconductor back surface in the dicing tape-integrated film for semiconductor back surface,
dicing the semiconductor wafer to form a semiconductor element,
irradiating the pressure-sensitive adhesive layer in the dicing tape-integrated film for semiconductor back surface with a radiation ray from the base material side,
peeling the semiconductor element from the pressure-sensitive adhesive layer of the dicing tape together with the film for flip chip type semiconductor back surface, and
flip chip-connecting the semiconductor element onto the adherend.
According to the process, the semiconductor wafer is attached onto the film for flip chip type semiconductor back surface in the dicing tape-integrated film for semiconductor back surface, and the semiconductor wafer is diced in a state that the back surface of the semiconductor wafer is protected. On this occasion, since the pressure-sensitive adhesive layer is not cured beforehand by irradiation with a radiation ray or the like, the close adhesiveness with the film for flip chip type semiconductor back surface is in a good state. Therefore, the occurrence of chip fly and chipping of the semiconductor element can be prevented. Moreover, at the dicing, cutting water is sprayed for cooling and prevention of the flying of cut swarf. According to the foregoing process, since the close adhesiveness between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface is good, the dicing can be performed while preventing the cutting water from penetrating between the both.
Furthermore, in the above-mentioned process, the pressure-sensitive adhesive force toward the film for flip chip type semiconductor back surface is decreased by irradiating the pressure-sensitive adhesive layer with a radiation ray from the base material side. Consequently, the semiconductor element can be easily picked up from the pressure-sensitive adhesive layer of the dicing tape together with the film for flip chip type semiconductor back surface without generating adhesive residue. Namely, according to the production process, the chip fly and chipping of the semiconductor element and the penetration of the cutting water between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface are prevented at the dicing step and also it becomes possible to well pick up the semiconductor element at the picking-up step.
Moreover, the present invention also provides a flip chip type semiconductor device which is manufactured by the process for producing a semiconductor device as described in the above.
According to the invention, in the dicing tape-integrated film for semiconductor back surface including a dicing tape including a base material and a radiation-curable pressure-sensitive adhesive layer on the base material, and a film for flip chip type semiconductor back surface formed on the pressure-sensitive adhesive layer, since a radiation-curable pressure-sensitive adhesive layer whose pressure-sensitive adhesive force toward the film for flip chip type semiconductor back surface can be decreased by irradiation with a radiation ray is adopted as the pressure-sensitive adhesive layer, picking-up of a semiconductor element can be well performed by irradiating the pressure-sensitive adhesive layer with a radiation ray before the picking-up (particularly, at the picking-up). Moreover, since the close adhesiveness between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface is good in a state that the pressure-sensitive adhesive layer is not irradiated with a radiation ray, the occurrence of chip fly and chipping of the semiconductor element can be prevented at dicing of a semiconductor wafer. Furthermore, at the dicing, cutting water is sprayed for cooling and prevention of the flying of cut swarf, but the penetration of the cutting water between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface can also be prevented. Namely, according to the configuration of the invention, it is possible to provide a dicing tape-integrated film for semiconductor back surface capable of exhibiting a good peeling property at the picking-up while preventing the chip fly and chipping of the semiconductor element at dicing and the penetration of the cutting water between the pressure-sensitive adhesive layer and the film for flip chip type semiconductor back surface.